Mask shell



FIG. 1 is a perspective view of a mask shell of our design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view.

Throughout the various figures of the drawings, certain views are not provided. The omission of a particular view is intended to convey that the element(s) depicted is/are plain and unornamented in that omitted view, or that the particular ornamental appearance in that view is simply not claimed.

Where included, broken lines showing environment or structure are for illustrative purposes only and form no part of the claimed design. Where included, dotted lines represent the border between claimed and non-claimed subject matter and form no part of the claimed design.

Where included, the use of stippling is intended to denote shading. 

The ornamental design for a mask shell, as shown and described. 